Continuous liquid treatment of textile materials

ABSTRACT

THERE IS PROVIDED AN APPARATUS FOR WET-HEAT TREATING A TEXTILE MATERIAL WHILE MAINTIANING THE TEXTILE MATERIAL IN A STRECHED, COMPLETELY RESTRAINED CONDITION. THE APPARATUS COMPRISES A TREATING VESSEL HAVING AN INLET AND OUTLET FOR THE TEXTILE MATERIAL, MEANS FOR INTRODUCING STEAM INTO THE TREATING VESSEL AND PESSURE SEALING MEANS FOR SEALING THE INLET AND OUTLET TO MAINTAIN AN ATMOPHERIC PRESSURE OF UP OT 3 ATMOSPHERE WITHIN THE TREATING VESSEL, WHILE PERMITTING THE CONTINUOUS PASSAGE OF THE TEXTILE MATERIAL THERETHROUGH. INLET RESTRAINING MEANS ARE POSITIONED EXTERIORILY OF THE TREATING VESSEL AND ADJACENT THE INLET, FOR RESTRAINING THE TEXTILE MATERIAL PASSING INTO AND THROUGH THE TREATING VESSEL. OUTLET RESTRAINING MEANS ARE POSITIONED EXTERIORLY OF THE TREATING VESSEL AND ADJACENT THE OUTLET, FOR RESTRAINING THE TEXTILE MATERIAL PASSING OUT OF THE TREATING VESSEL. THE OUTLET RESTAINING MEANS IS ADAPTED TO OPERATE AT A GREATER SPEED THAN THE INLET RESTRAINING MEANS TO ACCOMPLISH A 2-5% ELEONGATION OF THE TEXTILE MATERIAL. A PLUARILTY OF INTERIOR RESTRAINING MEANS ARE POSITIONED WITHIN THE TREATING VESSEL FOR MAINTAING THE TEXTILE MATERIAL IN A COMPLETELY RESTRAINEDF AND ELONGATED CONDITION DURING TREATMENT IN THE TREATING VESSEL.

NOV- 23, GR

CONTINUOUS LIQUID TREATMENT OF TEXTILE MATERIALS 2 Shoots-Shoot 1 Original Filed March 6, 1968 ATTORNEY-3 2 Sh0ets-Shoet 2 I'NVENTOR BY OASWM, "0mg 4 Msl mn ATTORNEYS M M: T h TENN; l HM w\ R w mm k N &

t mm J. E. GREER CONTINUOUS LIQUID TREATMENT OF TEXTILE MATERIALS Original Filed March 6, 1968 3,621,679 CUNTHNUOUS LIQUID TREATMENT (BE TEXTILE MATERlALS James E. GreenBox B2, Greensboro, NC. 27402 Application Mar. 6, 1968, Ser. No. 716,256, which is a continuation-in-part of application Ser. No. 292,389, July 2, 1963. Divided and this application Get. 31, 1969, Ser. No. 878,826

int. El. Dtlfic 1/00 US. Cl. 68-5 E 11 Claims ABSTRACT OF THE DTSCLUSTJRE There is provided an apparatus for wet-heat treating a textile material while maintaining the textile material in a stretched, completely restrained condition. The apparatus comprises a treating vessel having an inlet and outlet for the textile material, means for introducing steam into the treating vessel and pressure sealing means for sealing the inlet and outlet to maintain an atmospheric pressure of up to 3 atmospheres within the treating vessel, while permitting the continuous passage of the textile material therethrough. Inlet restraining means are positioned exteriorily of the treating vessel and adjacent the inlet, for restraining the textile material passing into and through the treating vessel. Outlet restraining means are positioned exteriorly of the treating vessel and adjacent the outlet, for restraining the textile material passing out of the treating vessel. The outlet restraining means is adapted to operate at a greater speed than the inlet restraining means to accomplish a 2-5% elongation of the textile material. A plurality of interior restraining means are positioned within the treating vessel for maintaing the textile material in a completely restrained and elongated condition during treatment in the treating vessel.

This is a divisonal application of US. application Ser. No. 716,256, now abandoned, which application was filed on Mar. 6, 1968 and is in turn a continuation-in-part of US. application Ser. No. 292,389, filed on July 2, 1963 and now abandoned.

The present invention relates to a novel method and apparatus for continuously stabilizing textile materials, e.g. nylon, in conjunction with the scouring and/or dyeing thereof. The invention is of special importance in connection with the treatment of narrow woven nylon fabric, notably nylon seat belting, where elongation and shrinkage must be carefully controlled within relatively narrow limits.

As is well known, many synthetic textile materials have undesirably high elongations when placed under mechanical loading, and, consequently, require stabilization when such an application is intended. Particularly critical is the stabilization of textiles used in the manufacture of tire cords and seat belting. Tire cord and seat belt textiles are standard items of commerce and in both cases have been stabilized by the manufacturer to have an elongation under mechanical loading within certain limits. However, the stabilization of these items of commerce leave much to be desired with respect to elongation and further stabilization is often required or at least desirable. Furthermore, in connection with seat belting, a dyeing operation is usually necessary. While tire cords do not require a dyeing, they are normally scoured or otherwise treated with fluids just prior to use to provide the clean materials necessary for proper binding. It has been a constant problem in the art to provide economical and effective processes whereby these textiles may be both further stabilized and fluid treated without lessening the eifect of the stabilization or largely destroying it al together.

inertia Patented Nov. 23, T971 Accordingly, the inventor sought an apparatus with which a fluid treatment such as dyeing or scouring could be carried out in conjunction with stabilization and which would produce a product of low elongation and minimum shrinkage, and, in the case of dyed seat belting, have a pleasing appearance and no crocking. This latter consideration of crocking is especially important in seat belting. Crocking (rubbing) refers to the dyed textile having the property of allowing some of the dye to rub off during use and is determined by :a standard test with a Crockmeter where a weighted projecting finger is rubbed over a surface of a dyed material and the amount of color transfer is compared with standards for evalution. As will be appreciated, a black dyed seat belt with unsuitable crocking properties could leave a dark smudge on a ladys white dress. Heretofore, it has been necessary to use complicated and very expensive processes to render the seat belting of acceptable crocking. The prior art processes required very large machines which performed numerous washings of the dyed seat belting with large quantities of water.

As noted above, the invention is particularly useful for seat belting but other types of nylon textiles in yarn and fabric form or the equivalent may also be advantageously processed according to the invention. Thus, nylon tow responds with surprising improvement when treated with the present method as well as other synthetic thermoplastic textile materials, e.g. polyesters and acrylics such as Dacron and Acrilan.

The term stabilization as used herein relates particularly to the shrinkage and elongation characteristics of the textile material undergoing treatment, the purpose being to so stabilize the textile that its shrinkage and elongation after processing fall within definite limits. The finished textile should have an elongation not in excess of about 15% and a shrinkage not greater than about 4% based on an individual filament or tow. In the case of woven seat belts, the elongation and shrinkage may be determined by dissecting the belt and testing an individual fiber or tow. Alternately a seat belt may be tested by pulling the belt to break and measuring the ultimate elongation. Similarly, shrinkage may be determined on a complete belt by dividing the dilference in the number of picks per inch prior to boiling and the picks per inch after boiling by the number of picks per inch after boiling. Thus, if the fabric has 18 picks per inch before boiling and 19 picks per inch after boiling the shrinkage is:

The nylon fibers making up the tow or woven fabrics (e.g. seat belting) useful in the present invention are those fibers which are commercially available. These fibers will have had a previous stretching and stabilization treatment, e.g. 2X to 10X stretch at room temperature or above with heat setting in a relaxed or restrained condition at room temperature or above as is well known in the art, which results in fibers of l to 900 deniers with tenacities of 3.5 to 8 grams per denier, elongations of 18% to and boil off shrinkages of about 6% to 15%. Moreoften, the fibers will have a denier of 15 to 840, an average tenactity of 4.1 to 7.5, an elongation of 18% to 53% and a shrinkage of about 8% to 12%.

The present invention is based on a number of important features. For one thing, the nylon or like textile is stabilized under wet conditions rather than in the dry state. This avoids degradation of the material and surprisingly gives faster stabilization than is possible in the dry state using the same temperature and time conditions. Another unusual advantage of wet stabilizing in the manner proposed herein is that lower temperature can be used. For example, stabilization with steam at 250 F. is equivalent to dry stabilization at 300 F. This means that the wet stabilized yarn remains stable even if subjected to dry processing at temperatures up to 50 F. higher than the stabilizing temperature. This is a surprising result and an improvement. In normal methods of heat setting in hot air or contact with a hot roller, it is generally accepted that the heat setting temperature must be 30 to 50 higher than subsequent exposure temperatures. Nylon that is heat set in normal methods of hot air or hot roll contact almost always turns yellow. This yellowing is most noticeable when heat setting unscoured greige yarns as received from the looms or yarn suppliers. This yellowing makes accurate shade matching quite difficult. For example, if a light blue shade of a nylon dye, e.g. Alizarine Lt. Blue 2GS is padded on and the belting then heat set in hot air (350 F.) for 5 minutes, a very greenish blue shade will develop while the next time these operations are carried out the shade will probably come up differently. Higher temperatures also make the nylon more yellow.

Besides yellowing, as mentioned, shade development of acid dyes or premetalized acid dyes by heat or thermosol-dry hot air methods is often poor and unpredictable. Nylon simply does not readily accept acid dyes by thermosol methods.

The apparatus described herein overcome the above faults. Thus, the nylon does not turn yellow; it is stabilized against shrinkage; and acid or premetalized dyes are readily dyed into the nylon with good results, excellent fastness and fixation. These results are not possible with hot air heat setting methods.

Furthermore, in carrying out the present process, it is important to have the nylon or other textile stretched out from its normal relaxed length after loom slack is removed (i.e. from about 2 to 5% elongation) and restrained from shrinkage during the wet stabilizing treatment. Rolls are used for this restraining action and it is another feature of the invention to utilize these rolls in such a Way as to minimize the number of rolls and roll bearings which actually bear the strain imposed by the nylon being treated. This has the advantage of minimizing wear and replacement costs in the system used for stabilizing the nylon.

As will be apparent from the foregoing, the principal object of the invention is to provide certain unique improvements in the stabilization of nylon, polyesters and polyacrylic, e.g. nylon tow and woven nylon such as belting. A more specific object of the invention is the provision of a process and apparatus for continuously wet stabilizing nylon or like textile in conjunction with some other liquid treatment such as scouring and/ or dyeing. A more specific object is to provide woven nylon seat belting which has been so stabilized that it does not exceed the maximum permissible elongation and wet shrinkage limits referred to above. Other objects will also be apparent from the following description of the invention and the accompanying drawings wherein:

FIGS. 1, 2, 3 and 4 are diagrammatic views of different embodiments of the apparatus for carrying out the invention.

Broadly stated, the objects of the invention are realized by causing a continuously running length of the nylon textile, e.g. tow yarn or fabric, to the action of steam or wet heat while being stretched out from 2% to 5% and restrained from shrinkage. The time of treatment will vary from about 1 second to 20 minutes, e.g. 1 to 7 minutes. Preferably, this treatment is carried out simultaneously with scouring and/or dyeing or some other type of hot aqueous treatment at the desired temperature. After the treatment the nylon textile is cooled to less than 230 F. prior to release of the tension. In the case of woven nylon seat belting or the like, the fabric is stretched at least about 2%, up to about 5%, in the warp direction after the loom slack is removed for the wet heat treatment described herein. About the same degree of stretch should also be used in the case where nylon yarn, either multifilament or monofilament, is treated. As noted above, the 2% to 5% stretch is based upon the length of the fabric or belting after the loom slack has been removed. In other words, the 2% to 5% stretch refers to a stretch of the fibers themselves in the warp direction in the case of a fabric. Of course, when fibers themselves, as opposed to a woven fabric, are being stretched, there is no loom slack. As will be appreciated by those skilled in the art, a 25% stretch of nylon fibers results in a strain within the elastic limit of nylon. That is to say that when the stress (stretch) is removed the fibers will return to their original length prior to stretching. This is, of course, directly opposite to the normal stabilization and stretching processes where the fibers must be stretched beyond their elastic limit, i.e. beyond the region where the fibers will return to their original length prior to stretching, e.g. about 8% or greater. It is indeed surprising that the present process is able to substantially alter the resulting properties of the fibers as the art heretofore believed that such a process would not effect properties. The reasons for this surprising result is not understood. However, some readjustment of the orientation must take place, since minor variations of the orientation normally present in commercially available fibers is substantially removed by the present process. Accordingly it has been noted that slight uneven dyeing normal with commercially available fibers is substantially eliminated with yarn processed according to the present invention.

The resulting elongation of the fabric or fibers or tow processed according to the invention is not in excess of 15% and shrinkage of not more than 4%. Furthermore, uneven dyeing, which results from the small variations in the orientation properties of the yarn constructing the seat belting, is eliminated by the present process. This is especially important in automobiles where the manufacturer goes to great trouble and expense to provide pleasing and harmonious automobile interiors. Also, but not least, the present invention eliminates crocking altogether. The seat belting of the present invention will not soil or stain white gloves and white dresses of ladies using these beltings. The present process is far more economical than conventional dyeing processes where large quantities of water and many washings of the conventionally dyed seat beltings are necessary to reduce crocking to a tolerable level. The present process requires an insignificant amount of water and only one washing. The present process is carried out with far less expensive equipment and the coat of processing is less than onehalf that of conventional processing. The seat belts produced by the present process have an elongation less than that heretofore obtainable with belts of comparable fiber deniers, width, and thickness and will prevent automobile passengers secured thereby from being bounced on such objects as steering wheels upon a collision impact, due to the greater elongation of comparable conventional belting.

For convenience, the invention is described in detail below using the accompanying drawings with particular reference to woven nylon seat belting although as noted, other materials such as polyesters or acrylics or other textile forms such as filament, tow, yarn and various different knitted or woven goods may also be treated in the manner described herein.

The embodiment shown in FIG. 1 comprises a closed treating vessel 2 made of steel or other suitable material. As shown, Greige belting or other textile N (e.g. tow, yarn, etc., as noted) is fed into the entrance leg 4 of the vessel and withdrawn through the exit leg 6. These legs are closed by means of appropriate pressure seals 8 which may be of any conventional type, e.g. as shown in US. Pats. 2,905,522 or 3,066,518.

The belting undergoing treatment in vessel 2 is elongated at least 2% and up to 5% of its normal length (after loom slack is removed) and maintained in this elongated condition and under complete restraint to preclude shrinkage therein. To this end, the vessel is provided with the inlet and exit restraining rolls 10 and 12, respectively, as shown. By operating rolls 12 at speeds greater than that of rolls 10 the requisite degree of stretch including the removal of loom slack is accomplished. The textile N should be cooled while passing through pressure seal 8 and rolls 12 e.g. to room temperature to 230 F. before the tension is released. If desired forced air or cooling water may contact textile N before the tension is released. In addition, a number of rolls 14 are provided in the vessel itself, the fabric being threaded through the vessel rolls 14 in such a way, as shown, that the strain in restraining the fabric from shrinkage occurs essentially on the two end bottom rolls designated by the arrows. Wear is thus centered on the support bearing for these two rolls. The other rolls 14 offset each other. Hence, it will be seen that the arrangement of FIG. 1 provides means for completely restraining the elongated fabric from shrinkage with a minimum of bearing wear points.

When simultaneously scouring and stabilizing, the treating liquid in vessel 2 may comprise water and an appropriate scouring detergent, e. g. Charlasol F68 (Charlotte Chemical Labs), at any appropriate stabilizing temperature, e.g. one in the range of 240 to 300 F., typically 260 F. This means that the space above the liquid level L is filled with steam which serves to stabilize the fabric in the scouring operation. The pressure in the vessel will naturally depend on the temperature utilized but usually falls in the neighborhood of 2 to 3 atmospheres. As will be appreciated, the belting after being stretched 2% to 5% contacts steam (water vapor above the liquid water) in leg 4, hot water in the vicinity of rolls 14 and steam (vapor) again in leg 6. Hence, in this embodiment the wet heat is a combination of steam/water/steam.

The time of treatment in vessel 2 will necessarily vary depending on such other operating factors as the temperature and nature of the nylon fabric undergoing treatment. As an example, however, it can be stated that conventional nylon seat belting comprising 18 picks and ends of 840 denier, 140 filament nylon can be scoured and stabilized at 260 F. in the arrangement of FIG. 1 in from 2 to 6 minutes, typically 5 minutes. Of course, the water could be replaced by a dye solution and the stabilizing would therefore be accomplished in conjunction with a dyeing operation.

It will be appreciated that the arrangement in FIG. 1 provides a way for continuous scouring or dyeing while stabilizing a web or tow comprising nylon or like synthetic thermoplastic heat-settable textile material. In the case where scouring is performed, the nylon or the like may be fed to a dyeing operation with or without an intermediate washing operation. Generally, however, it is advisable to dry the material under low tension before dyeing. The water wash and drying step, if used, and the dyeing may also be set up for continuous operation so as to provide a continuous arrangement for scouring, stabilizing and dyeing. The number of rolls in scouring vessel 2 may be appropriately selected to give the desired retention time in the vessel to facilitate scouring and provide for continuity in subsequent operations.

If the dyeing operation follows scouring and stabilizing according to FIG. 1, the dyeing may be carried out with the fabric in the relaxed condition provided the scouring temperature exceeds the dyeing temperature by from about 20-30 F. Conventional dyeing procedures may be used but one highly effective way of dyeing scoured and stabilized belting or other materials as visualized herein involves using the system shown in FIG. 2.

Thus, as shown in FIG. 2, the belt N, after scouring and stabilizing by means of the apparatus and method illustrated in FIG. 1, is fed into the funnel shaped entrance end 15 of the dyeing tube 16 which, while referred to as a tube herein for convenience, may have any desired cross-section, e.g. circular, rectangular or square.

The tube 16 is filled vw'th hot aqueous dyebath at the desired dyeing temperature, e.g. 210-220" F. Temperatures above the normal boiling point may be obtained without cavitation by, for example, applying heat at the bottom of the tube and using a tube height which is sufficient to give an appropriate liquid head and pressure at the bottom of the tube sufiicient to avoid boiling. As an alternative, the inlet and outlet ends of the tube may be provided with pressure seals to permit operations above the normal boiling point while keeping the tube height at a minimum.

As shown in FIG. 2, the textile material passes downwardly through the heated dyestuff solution in the entrance leg 17 and transverse intermediate section 18 and then upwardly through the exit leg 19, the latter being enlarged to provide a retention chamber 19' for the material being treated. Since the textile material has previously been stabilized, during the scouring operation, it is preferably in the relaxed condition as it is moved through the tube. Movement of the material through the tube is preferably accomplished by circulating the dye solution through the line 20, pump 21 and the annular spray pipe :22 at the inlet end of the tube. A heat exchanger 24 is also provided to maintain the desired temperature.

The treated material is withdrawn from the tube 16 by roll means 26 as it comes to the top of the retention chamber 19. Usually, the flow rate and other conditions are such as to give a total treatment time in the area of 4 to 8 minutes in tube 16 although the time selected for any particular situation will depend upon the other operating conditions. However, for dyeing conventional woven nylon seat belting having the construction indicated heretofore, a treatment time of about 5 minutes at 240 to 270 F., is satisfactory. If desired, the rolls 26 or other means may be used to move the textile material through the tube although, as indicated, the liquid circulation preferably serves as the sole essential means for moving the material.

The dimensions of the treating tube 16 may be widely varied. As a typical example, however, the legs 17 and 19 may be 3-6 feet high or even higher, e.g. 20 feet, and the intermediate section 18 may be relatively short, l3 feet being illustrative, or quite long, e,g. 1015 feet or more. If the tube has a circular cross-section, the diameter of the legs 17 and 18 may be of the order of 26 inches with the enlarged leg 19 approximately double this diameter. Obviously, the tube dimensions should be sufficient to permit the fabric or other textile material to pass easily therethrough while providing the desired retention time and it will be recognized that in some circumstances, depending on the nature of the material undergoing treatment, etc., it may not be necessary to enlarge the exit leg 19 for retention purposes. Thus, while FIG. 2 shows the textile folded lightly over itself in the retention chamber 19', the rate of treatment or the nature of the textile in some cases may be such that there is no substantial folding over of the material during treatment.

Any conventional formulation for dyeing the particular textile involved may be used in practicing the present invention. Such formulations will usually comprise an appropriate dyestuff dissolved or dispersed in water with a carrier such as aromatic alcohol mixtures as described in US. Pat. 1,817,205, e.g. Charlasol SD, to accelerate the dyeing. Such dye formulation may be automatically metered into the tube 16, for example, at inlet end 15 to make up for dyestuff taken up by the material being dyed.

Black is the leading, most important, shade for dyeing nylon such as tow, flocked goods, automotive seat belting and other fabrics and it is common practice to dye the nylon black with the use of black acid dyestuffs,

such as: Cibalon Black BGL, color index #107; Gycolan Black WAG, color index #52; or acid black mixtures such as Durol Black 23, color index #24. However, with prior procedures these dyestuffs do not give a really full, jet black color that is so desirable. It is also well known that Logwood Black can give an extremely attractive, deep, full, bloomy black on nylon, but attempts to dye Logwood Black onto nylon belting or tapes by prior continuous methods (pad/steam) have not been successful. Often the fastness is poor, especially the fastness to crocking which must be extremely good to meet the requirements on, for example, safety belting and tapes. Attempts to dye Logwood Black onto nylon in batch methods also have not been completely successful because of premature oxidation of the Logwood Dye itself, in any type of machine where the nylon is exposed to the air, such as a rotary machine, or a Buhlman machine, or a tub or beck and, from the very nature of the narrow fabrics and tapes, it has been practical to dye these in closed machines, such as a beam machine, or a cheese or package machine.

In contrast to the above noted prior art practices, the dyeing technique illustrated in FIG. 2 has been found to.be highly effective for continuously dyeing nylon belting or other narrow fabrics using any of the conventional nylon dyestuffs, e.g. the standard black acid dyestuffs. The results are especially satisfactory in the case of Logwood Black which gives excellent fastness to crocking and a black shade which is much deeper, fuller and more attractive than those otherwise obtainable.

A typical formulation for dyeing automotive safety belting (comprising, for example, 18 picks and ends per inch of 840 denier, 140 filament nylon Type 6 or Type 66) according to the system shown in FIG. 2 may comprise the following on a liter basis:

50 grams/liter Logwood Paste 55 (American Dyewood .4 cc. acetic acid 30.0 cc. Charlasol SD (Charlotte Chemical Labs.)

Balance: water In use, the tube 16 may be filled with the above dyeing formulation at 210 F. and the seat belting dyed therein using a dyeing time of minutes. The thus treated fabric N may then be continuously fed from the rolls 26 into a second tube 28 as shown in FIG. 2. This second tube is preferably identical with tube 16 and may be filled with an appropriate oxidizing solution, e.g. one having the following composition per liter:

1.5 grams/liter sodium bichromate .4 cc. acetic acid Balance: water This oxidizing treatment may be carried out at 200 F. for the same time period as the dyeing in tube 16, i.e. about 5 minutes. The thus treated fabric is withdrawn from the exit end 30 of tube 28 by rolls 32 and may then be rinsed, soaped off lightly and dried to give a highly desirable black dyeing. The product has an extremely low level of crocking or no crocking at all after only one scaping and rinsing.

As shown in FIG. 2, the tube 28 is provided with appropriate liquid circulating means as in the case of tube 16 comprising the take off line 34, pump 36, heat exchanger 38 and spray pipe 40 in the inlet end 42 of tube 28. Means (not shown) for rinsing the fabric N with water between rolls 26 and the inlet rolls 44 of tube 28 may also be provided if desired.

The system shown in FIG. 2 represents a highly effective way for dyeing conventional nylon belting black or in some other color. The dye solution may be retained in the tube after each run so that the system is very economical. If desired, the fabric may be padded with the dye formulation before it enters the tube 16 but this is not essential. It will also be appreciated that the fabric may be stabilized in conjunction with the dyeing operation by placing appropriate restraining rolls (not shown) at the inlet and outlet ends of the tube 16, the outlet set of rolls be adapted to have a speed greater than the inlet set of rolls. With this arrangement, the textile may be stabilized in the dyeing operation while being elongated 2% to 5% and in a completely restrained condition. In this case, it is preferable to close the ends of the tube by means of appropriate pressure seals to facilitate the use of stabilizing temperatures above the normal boiling point. Thus, as it will be appreciated, the belting is stabilized by contacting a steam (vapor above the liquid in leg 16)/ liquid combination.

The significance of the present process for dyeing nylon seat belting is stressed by the fact that belting woven with nylon Type 66 can be dyed, just as well as Type 6 nylon, to give an extremely full, deep, jet black with excellent fastness, using, for example, Logwood Black dyestuff, Durol Black 2B, or Cibalon Black BGL with Charlasol SD. This is highly unusual because nylon Type 66 is not generally as readily dyed as Type 6 nylon and does not usually give as deep a black shade using the same dye formula. It should, however, be clearly understood that the process is applicable to any of the conventional nylons, e.g. nylon 6; 66; 610; 11; and 12 and mixtures thereof.

While highly effective results are obtained by dyeing the nylon in the system of FIG. 2 after stabilizing by the method illustrated in FIG. 1, superior results are realized if the nylon is stabilized as a part of the dyeing operation in a manner noted above in connection with FIGS. 1 and 2. To this end, it will be appreciated that the arrangement of FIGS. 1 and 2 may be used for continuously stabilizing and dyeing nylon, rather than scouring and stabilizing. In this event, the scouring operation may be carried out on the greige goods in any conventional fashion, including the relaxed state, and preferably in a continuous manner so that the scouring, stabilizing and dyeing may be effected in a continuous series of operations.

Since, it has been found that stabilizing nylon simultaneously with the dyeing operation produces superior results, an apparatus especially designed with this thought in mind is shown in FIG. 3. In this particular embodiment, a molten metal seal is disclosed but, in lieu of this, pressure seals of the type referred to heretofore (U.S. Pats. 2,905,522 and 3,066,518) may also be used as shown in FIG. 4.

In this system of FIG. 3, the belting or other nylon textile is again stretched out at least about 2% and up to 5% and held in this stretched condition throughout the dyeing and stabilizing operations. Here again, for convenience, the treatment of woven nylon fabric F is referred to for descriptivepurposes although, as noted heretofore, other textile forms and compositions may be used. As shown, the fabric F, after scouring the greige goods in any conventional fashion is fed through the first set of restraining rolls 46 into the treating vessel 48 which may be constructed of steel or other suitable material and may have any appropriate cross-section, e.g. circular or rectangular. Within the vessel 48, the fabric is first passed through dye solution 50 and then through the molten metal seal 52. While passing through the seal, the fabric goes around restraining roll 54 and then passes from the seal into a steam chamber 56 provided within the vessel between the closed end 58 and the seal 52. Steam is fed into the chamber 56 by means of inlet 60 and condensate is withdrawn through outlet 62.

The nylon F is circulated back through the vessel by passing the textile material around an end roll 64, under another restraining roll 66 which is positioned opposite roll 54 and then out through the exit restraining rolls 68. From this point, the fabric may be fed continuously to appropriate washing and drying treatments and/or whatever other operations may be desired. The nylon F will normally require only one washing to reduce the crocking to a very low or nil level, but if desired two or more washings may be performed. The temperature of the wash water is preferably close to the stabilization temperature used during dyeing and stabilizing, but if it is above 240 F. or slightly higher, the washings must be carried out with the nylon F in a restrained condition as in the dyeing and stabilization operations.

The steam chamber 56 should be operated at a temperature sufiicient to complete the desired dyeing action and stabilize the fabric against subsequent treatments. As indicated heretofore, this temperature will usually be in the range of 240 to 300 F., e.g. 250 F, and the time of treatment will be in the neighborhood of 2 to 6 minutes. These time/temperature conditions may be used to give highly effective dyeing and stabilizing using saturated steam at 15 to 25 p.s.i.

While the shape of the vessel 48 may be varied, e.g. the vessel may be V- or U-shaped, it is important to have at least the inlet end of the vessel suficiently high to accommodate the liquid differential or head H created by the steam pressure and to otherwise maintain the desired liquid metal seal against this pressure.

Any of the conventional liquid metal seals may be utilized herein. One known as Alloy 15" having a melting point in the range of l95200 F., may be mentioned as an illustration for use with steam at 15 pounds pressure and 250 F. However, other molten metal seals may also be employed.

It will be noted that the roll 66 is smaller in diameter than the roll 54 in order to space the incoming and outcoming sections of the fabric. Additionally, it will be seen that the arrangement of FIG. 3 includes only three rolls within the vessel. This means that there are only three roll bearings put under strain by the nylon undergoing treatment apart from the inlet and exit restraining rolls which must in any event be used. Thus, the arrangement of FIG. 3 requires a minimum number of rolls and bearings subjected to strain. This strain is very substantial and necessitates frequent changing of roll bearings. Conventional agers and dye ranges may have as many as 44 roller bearings which must be frequently replaced because of the wear and strain thereon. Hence, reducing the number of bearings under strain to three according to the invention represents a very important advantage.

As in the other specific embodiments described herein, the arrangement of FIG. 3 may be used for dyeing nylon in all shades and colors conventionally employed, e.g., black, yellow, gold, etc. It will also be appreciated that the embodiment of FIG. 3 may be used for stabilizing nylon with a liquid and/or steam treatment other than dyeing, e.g. scouring or the like, as in the case of the arrangement shown in FIG. 1.

The following conditions may be given as illustrative when using the arrangement of FIG. 3 for continuously dyeing and stabilizing nylon seat belt fabric (2 inches wide and comprising 18 picks and ends per inch of 840 denier, 140 nylon Type 6 or 66), the fabric having been previously scoured in greige form at 140 F., in a soda ash, Varsol, Sterox SK mixture (proportions 1:5 :1 by weight) DYE SOLUTION (PER LITER) 50 grams Durol Black (acid dye) 28 (Allied Chemical). 20 cc. Charlasol SD.

2 cc. acetic acid.

Balance: water.

This forms a thickened solution quite suitable for padding.

Time of treatment: minutes.

Metal seal Alloy at 196 F.

Elongation: 2% fabric stretch during treatment (1" stretch per 44 inches normal unstretchcd length).

Steam chamber: saturated steam at 250 F.

Steaming time: 5 minutes.

The metal seal effectively serves as a pad for application of the dyes. The same is true if a pressure seal is used.

10 Subsequent treatment: Washed one time at 240 F under total restraint and dried at F. to give highly desirable color characteristics and complete stabilization.

As can be seen from FIG. 3 the fabric P will pick up dye as it passes through the dye solution. The dye picked up will not be disturbed by the liquid metal seal. The liquid metal seal is, of course, heated by a conventional means, as electrically, to a suitable temperature e.g. F. As the fabric passes through the liquid metal seal it is preheated up to the temperature of the liquid metal seal, but to a temperature below its appropriate stabilization temperature. After passing through the liquid metal seal, the fabric enters steam chamber 56 where the bulk of the dyeing and stabilization takes place while the fabric is stretched from 2% to 5%. The fabric then passes again through the liquid metal seal and is cooled to the temperature thereof. The fabric again passes through the dye solution, but little if any additional dyeing takes place during this second pass as the dye solution is not heated to the necessary temperature. As can be appreciated, in this embodiment, the fabric is dyed and stabilized with wet heat or steam only.

FIG. 4 illustrates another way of stabilizing a textile material simultaneously with a dyeing operation and is a preferred embodiment. In this case, a mechanical pressure seal acts as a combination pad for the dye and as a seal to contain the pressure. A liquid level control (not shown) on the pad-pressure seal unit maintains the dye solution at a constant level to insure even dye padding.

As before, the material to be treated according to the system of FIG. 4 may be either nylon tow, filaments, yarns or fabrics; or others such as polyetser or acrylic fiber. Material M to be treated stretched at least 2% and up to 5% and held by the restraining rolls 68, is fed continuously through a dye pad-pressure seal unit 69, the dye composition being shown at 69a. The material then goes into the inlet leg 70 of tube T, under a substantial roller 71 in the intermedaite section of the tube and around roller 72 at the closed end of a lateral, angularly disposed extension or steam chamber 73 of tube T. The material M then returns to pass around roller 74 in the intermediate tube section 75, up the exit leg 76, out through pressure seal unit 77, around restraining device 78 which is adapted to operate at a greater speed than roll 68 to accomplish the required stretch, and onward to be rinsed, dried and finished, or otherwise treated. Steam may be fed into the tube T as shown. If desired, the intermediate section 75 may be filled with water extending up into the tube legs 70 and 76 and extension 73. In such a case the material M, after being stretched and padded with dye rotation, first contacts steam in the upper part of leg 70, the water in the lower part of 75 and 73, then steam at the outer end of 73 near roll 72, then water again in 75, if the level of the water is high enough and steam again in leg 76. Or, as noted above, the tube T may contain only steam, except for a small amount of condensate at the bottom of 75. However, when the tube T contains water at the bottom of 75 and optionally up into legs 70 and 76, the dye picked up by the material M is partially set in leg 70 and further set in 75 and 73. Upon return around roll 74 and through leg 76, the material M is washed while in the restrained condition, and of course at the dyeing and stabilizing temperature, to the extent that no further rinse, or perhaps only one further rinse, is necessary, to effect a very low or nil level of crocking. Of course, in this embodiment it would be necessary to occasionally change the water in 75 or continually replace the water in 75 with fresh make-up water. The tube, particularly steam chamber 73 is operated at a temperature sufficient to complete the dyeing action and to stabilize the material M being treated. This will usually be in the range of 240 to 300 F. for about 5 minutes.

As can be seen from the above disclosure, an important feature of the invention is the stabilization of fibers or fabrics with wet heat at a temperature between about 240 F. and 300 F. while being stretched about 2% to 5%. Ideally, the wet heat is supplied by an aqueous scouring or dyeing solution. The wet heat can be steam and/or hot Water or any combination in sequence thereof. The process can be carried out by scouring, optionally with a dyeing, and conventional washing thereafter. However, for superior results in connection with dyeing, the dyeing and stabilization must be carried out simultaneously, and optionally with a subsequent hot water washing. The textile so processed normally will require only one further washing. Preferably, the hot water washing temperature is near or at the dyeing and stabilization temperature and conducted under restraint as in the dyeing and stabilization operation, e.g. near or above 240 F.

Various different applications and modifications of the inventive concepts described above are contemplated herein. For example, nylon carpet strips or fabric may be treated according to the invention and instead of working with woven nylon fabric, it is possible as indicated heretofore, to use the invention to stabilize nylon yarns or tow before weaving. Thus, for example, warp yarns may be subjected to the present wet heat treatment in the stretched condition in order to obtain the desired stability. Yarn as received from the manufacturer usually is nonuniformly heat set and, as a result, demonstrates varying dyeing characteristics. Application of the stabilizing treatment of the invention to such yarns eliminates these variations and gives a substantially improved product. Another advantageous area of use is in the stabilizing of tire cord to eliminate so-called flat spotting. The nylon tire cord yarns are stabilized by stretching and continuous exposure to wet heat, steam or water at elevated temperature; example 240 to 300 F. This exposure to wet heat, water or steam, at elevated temperature while restraining the nylon at the same time, gives far superior setting to the nylon. Other areas of use for the present invention in the treatment of nylon, polyester and/or acrylic textiles, including but not limited to yarns and tows and fabrics prepared therefrom will also be apparent. It will also be understood that the term nylon as used herein refers to synthetic linear polyamides, including the well known Types 6 and 66, but not limited thereto.

Further, any of the conventional filaments or tows may be used, e.g. 1 denier or lower to 900 denier or higher with or without twists such as 0 to 6 /27 turns per inch or tows with 100,000 total denier or lower and up to 300,000 total denier or higher. The nylon filaments or tows normally will be at least partially oriented by conventional drafting, e.g. 2 to 10 times at temperatures of from room temperature up to below the melting point of the particular nylon. The drafted nylon filament or tows will have a tenacity of between about 3.5 to 8 grams per denier and an elongation of about 18% to 60% at room temperature. Further, the nylon filaments or tows will normally have had a further treatment to reduce shrinkage, e.g. heat set or heat relaxed plus some lagging, whereby the residual shrinkage at boil-off is between about 6% and Any of the conventional fibers or tows, as described above, either alone, or after being woven into textiles, such as seat belting, may be used in the process of the invention. Seat belting refers to those standard items of commerce which are woven from conventional synthetic plastics such as the nylon described above. A conventional seat belt is constructed of 18 picks and ends of 840 denier, 140 filament nylon although other constructions may be used, e.g. 14 to 24 picks and ends ofl 100 to 900 denier, 10 to 300 filament nylon.

What is claimed is:

1. Apparatus for stabilizing and dyeing a textile seat belt material while retaining said material in a stretched,

completely restrained condition comprising a dye pad and a treating vessel having an inlet and outlet for said textile seat 'belt material, means for introducing steam at temperatures between 250 F. and 300 F. into said vessel, pressure sealing means for sealing said inlet and outlet to maintain a pressure of up to 3 atmospheres within said vessel while permitting the continuous passage of said material therethrough, exterior inlet restraining rolls positioned exteriorly of said vessel and adjacent said inlet for restraining the said material passing into and through the vessel, exterior outlet restraining rolls positioned exteriorly of said vessel and adjacent said outlet for restraining the said material passing out of said vessel and said outlet restraining rolls being adapted to operate at a greater speed than said inlet restraining rolls to accomplish a 2-5% elongation of said textile seat belt material, said vessel having at least one lateral extension thereof and roll means disposed in the outer portion of said lateral extension for passing the said textile seat belt material from the said vessel, through said extension, around said roll means and back into said vessel while maintaining the said restrained and elongated condition of said textile material.

2. Apparatus according to claim 1, wherein the said sealing means are mechanical pressure seals.

3. Apparatus according to claim 1 wherein the restraining means are means for continuously passing the seat belt material into, through and out of said vessel.

4. Apparatus according to claim 3 wherein said inlet and outlet restraining means are in the form of a set of two rolls positioned outside said vessel adjacent both said inlet and outlet, respectively.

5. Apparatus according to claim 1 wherein the said vessel has interior restraining means in the form of at least one set of rolls within said vessel for maintaining said material in the elongated, completely restrained condition during treatment.

6. Apparatus of claim 1 wherein the said lateral extension and said roll means therein define a U-shaped path which is traversed by the said textile material while passing therethrough.

7. Apparatus according to claim 1 wherein said mechanical pressure seals also act as a dye pad.

8. Apparatus according to claim 1 wherein said lateral extension is disposed angularly with respect to said vessel.

9. Apparatus according to claim 8 wherein said lateral extension is adapted to contain water in at least a portion thereof adjacent said vessel.

10. Apparatus according to claim 1 wherein the said vessel is adapted to contain water in a lower portion thereof for contacting said seat belt material during passage thereof through said vessel.

11. Apparatus according to claim 1 wherein the said vessel has means for introducing water into and removing water from said vessel.

References Cited UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,621,679 Dated November 23, 1971 lnventm-(s) James E. Greer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, in the heading, after "James E. Greer, Box 2, Greensboro, N.C., 27 l02" insert --Assign0r to Burlington Industries, Inc., Greensboro, N.C.-.

Signed and sealed this 30th day of May 1972.

(SEAL) Attes EDWARD 1Z.FI..E']JCIER,JR. ROBERT GOITSCHALK Attesbing Officer Commissioner of Patents DR P USCOMM-DC 00376-POD Q 5, GOVEINIIEIT IIIIIYING OFI'CI I. D-III-lll 

